[jreaves1637]

I need your guys help deciding which way I should go or at least pro's and con's on each. I am looking to buy a 21" maelstrom in the next couple of days and can't decide wether to go sealed or also get 2
21" passive radiators from kevin. I am going to power which ever design I go with the with Face Audio 1200 amp from Kevin also. I have had some sealed subs in the past and thought they sounded great and I also had a passive radiator design from Klipsch many many years ago and like it also. Can anyone tell me what I would lose / gain from going with either design to help me make a educated desicion? The room will be a dedicated HT room so size isn't that much of a issue and is 26x13x8 with a small hallway off it it which is about 10x4x8. Also this will be my first DIY sub build so anything I didn't mention etc please let me know.

thanks for any help you can provide.

 

[Mike P.]

Re: deed your help deciding

A Passive Radiator design will have more low end out put compared to a sealed design, it's what I'd go with since this is for HT.

 

[jreaves1637]

will the passive radiator design have more overall output in general vs the sealed?

 

[jreaves1637]

do you think the 21" and 2-21" pr's be overkill for this size space and go with the same setup but with 18"er's

 

[jreaves1637]

I was looking around on the face audio website and found this below. Maybe Kevin or someone can comment but should I be worried about running the maelstrom with this amp in bridged mode?

"A: Bridge/Mono mode allows a higher load (usually around 2ohms) to be handled more effectively by the amp. It puts the amplifier into a "push, pull" configuration, utilizing both sides of the amp into one single output. Our real answer here is that you should only run in bridged mode when you simply have no other choice. You should always choose the right amp for the load being placed on it. Sometimes, however, you get stuck in a situation requiring more power than you have at hand in stereo mode. Bridged mode can allow you more power handling capabilities in a pinch. We don’t recommend making it a habit."

 

[jreaves1637]

also I was looking at my room again (still under construction) and it would appear the 18 with 2 pr's would be suffice and I would save $300 in the process but I hate to go through all this work and not be happy or it not be enough. Would I be selling myself short by going with the 18 and 2pr's instead of the 21's? Would the box size between the 2 be a huge difference in size? I don't know what size either would need to be?

 

[Mike P.]

Depending on what you want for out put levels, either a 21" with PR's or a pair of ported 18" is what I would do. The 18"s don't need PR's, there are lots of ported builds in the Database.

 

[fredk]

Nobody 'needs' a Corvette to drive to the corner store either.

 

[Kevin Haskins]

In general, as you go up in size, you go up in output. If you don't have size constraints that allows you to design around significantly more output. HT requires a lot and if you have a dedicated room/system, it makes sense to make sure you have enough output when you are done. A couple hundred dollars tends to be 10% of the budget of most systems so it seems foolish to me, when you have the budget and the space to go half way. You can be penny wise and pound foolish.

Ports and PRs are a method at getting more output from a given driver. Sealed systems will have less output, but many people like the way they sound. As a general rule of thumb, you need two sealed drivers to equal the output of the ported or PR system (that is a really BIG generalization). They also require different design constraints in terms of size/layout/and the need for subsonic filters. So... there is no free lunch.

Give me a call.... that is probably the best way of addressing all your questions in a efficient manner.

360-452-9373

Kevin Haskins
Exodus Audio

 

[jreaves1637]

Talked with Kevin and I'm going with a 21" maelstrom in a sealed enclosure powered by a face audio 700 amp. May add a second amp and 21 later.

Thanks Kevin for all your help.

 

[Drizt]

Talked with Kevin and I'm going with a 21" maelstrom in a sealed enclosure powered by a face audio 700 amp. May add a second amp and 21 later.

Thanks Kevin for all your help.

Your going to be extremely happy with that choice once its all done

 

[Lonely Raven]

Talked with Kevin and I'm going with a 21" maelstrom in a sealed enclosure powered by a face audio 700 amp. May add a second amp and 21 later.

Thanks Kevin for all your help.

Keven talked me into a 21" sealed as well, but I already had an EP2500.

I'm pretty happy with it as I learn to re-learn what good deep bass sounds like. My old sub was no slouch, but didn't have the depth of the 21". An 18" ported may have been a bit louder at 15Hz, but so far I'm not feeling I'm left wanting. Also, the 21" in a sealed box sounds surprisingly good with music...I'm finding myself playing music in the theater more often now, and enjoying very epic (musical) soundtracks.

 

[jreaves1637]

that is awesome. I can't wait to get mine and start working on it. I am leaning towards baltic birch 13-ply if I can find it.

 

[jreaves1637]

It will prolly take a week or so to get my sub and amp in. I went with the FA 1200 instead of the 700 just to have some headroom. Kevin if you read this that shouldn't be a problem you think? How much can these 21" subs safely handle? Would it be better to have the bigger amp with more headroom than to have the smaller and clip the signal? I can never make up my mind grrrr. I do thank Kevin for putting up with me.

 

[Kevin Haskins]

It will prolly take a week or so to get my sub and amp in. I went with the FA 1200 instead of the 700 just to have some headroom. Kevin if you read this that shouldn't be a problem you think? How much can these 21" subs safely handle? Would it be better to have the bigger amp with more headroom than to have the smaller and clip the signal? I can never make up my mind grrrr. I do thank Kevin for putting up with me.

I have many customers using Maelstrom-18" & 21" builds with up to 3000W amplifiers. It isn't a problem using too much power as long as you use common sense.

You don't need it necessarily. The F700-TS for $500 is actually plenty of power and the sale price on the overstock is a really good deal. It would be about 2600W into the Maelstrom and that is plenty. If you were going to use it in a heavily equalized small sealed box is the only time I'd concern myself with not having enough headroom with the F700-TS.

Kevin Haskins
Exodus Audio